The
menstrual cycle occurs in women and periods can begin as young as age seven, but
in populations not affected by environmental poisoning, they generally start at
about age twelve to fifteen years. menstruation can start before or during the
growth of breasts.

Menstruation and ovulation results from of a very complex and delicately
balanced chemical cycle that mature females go through every month or so.

What is a menstrual cycle?

The menstrual cycle is how a woman’s body prepares for the
possibility of pregnancy each month. A cycle usually averages about
28 days long and starts on the first day of a period. However, a
cycle can range anywhere from 23 to 35 days.

What is a menstrual period?

The menstrual period is a woman’s monthly bleeding. A girl’s period
may not be the same every month, and can vary from girl to girl.
Periods can be light, moderate, or heavy, and the length of the
period also varies. While most menstrual periods last from three to
five days, anywhere from two to seven days is considered normal. For
the first few years after menstruation begins, periods may be very
irregular.

Sanitary pads or tampons, which are made of cotton or another
absorbent material, are worn to absorb the blood flow. Sanitary
napkins (pads) should be changed as often as necessary, before the
pad is soaked with menstrual flow. Tampons should be changed every 4
hours. Make sure that you use the lowest absorbency of tampon
available.

What happens during the cycle?

There are four phases of the cycle, the first phase is menstruation – or having your period. The lining
of the uterus (the endometrium) breaks up and flows from the uterus
through the small opening of the cervix, and passes out of the body
through the vagina. The menstrual flow is actually a mixture made up
of blood, mucus, and body cells. The flow might be red or quite
dark, and might include some clumps or clots. Most menstrual periods
last from three to five days.

The second phase is pre-ovulation phase. Right after your period
ends, the ovaries start to prepare another egg, or ovum, for release
in the fallopian tubes.

The third phase is ovulation. Here, the egg is released from the
ovary into the fallopian tubes. If the egg becomes fertilized by a
sperm cell, it attaches itself to the uterine wall and a fetus will
begin to develop. Ovulation usually occurs 14 days before the start
of your next period.

The fourth phase is the premenstrual phase. If the egg is not
fertilized, the thickened lining of the uterus is shed during the
menstrual period, as a new menstrual cycle starts all over again.

How
long does a woman have periods?

A woman will no longer be able to reproduce once she reaches
menopause, usually around the age of 50. Menopause means that a
woman is no longer ovulating (producing eggs) and therefore can no
longer become pregnant. Like menstruation, menopause can vary from
woman to woman and may take several years to occur.

Some
gynecologists recommend that patients prone to yeast infections
stay away from brands of pads with plastic "top sheets" (ie: Always),
which are more likely to get sweaty and wet. I do know that grooming
habits are important: only wipe front to back, including when
changing babies

Getting your period is a normal and healthy part of being a woman.
Young girls should not be terrified, rather should be prepared for
puberty’s biggest event - having your period or menstruating.
Menstruation begins during puberty, usually 12 or 13, but it can
start anytime between 8 and 16.

The Chemistry:

We'll start with your hypothalamus, which is a gland in your brain.
It sends chemical messengers all over your body to control many body functions,
including eating, sleeping and menstruating. The hypothalamus is sensitive
to stress and other things going on in your life, so just as you might
be unable to sleep if you are excited or upset, your menstrual cycle may
also be influenced by your moods.

The hypothalamus keeps track of the hormone levels in your blood. At
day one of your menstrual cycle, the first day of your period, the levels
of estrogen, an important hormone for women, become very low. The hypothalamus
responds by telling the pituitary gland, which is also in the brain, to
send two kinds of hormones into the bloodstream. One hormone is called
Lutenizing Hormone (LH) and the other is called Follicle Stimulating Hormone
(FSH). These two hormones are made especially to encourage your ovaries
to produce an egg.

When the LH and FSH arrive at the ovaries, they stimulate the growth
of 10 to 20 follicles. A follicle is a little bundle of cells that contains
an undeveloped egg. Follicle means "bag" or "sack"
in Latin. You have around 400,000 follicles in your ovaries when you are
born, more than enough for a lifetime.

As the follicles grow, they start to produce the hormone
oestrogen. The
oestrogen causes the lining of the uterus - the endometrium - to begin to
grow again. Remember, this started on the first day of the cycle, when
the bleeding began. The uterus lining is completely shed now, and needs
to start growing again.

Around day 14, one of the follicles is bigger than all the others. It
holds the egg that will be released this month The oestrogen levels are
very high at this point. The pituitary responds by decreasing the FSH it
has been releasing, but increasing the LH. This jump in the level of LH
is what causes the giant follicle in the ovary, now called the Graafian
follicle, to burst open and explode right through the ovary wall, releasing
the egg. This is ovulation.

The ends of the Fallopian tubes are covered with little wavy fingers
called fimbria. The fimbria pull the newly released egg up into the Fallopian
tube, where it will spend 12 to 36 hours moving toward the uterus. It is
during this time that fertilization could occur if it meets a sperm. Only
one ovary is stimulated per cycle, and one egg is released. Once in a while
two eggs are released, and this results in fraternal twins, twins who are
not identical because they came from two eggs and two sperm.

Back in the ovary, the exploded follicle still has work to do. It is
now called the corpus luteum, Latin for "yellow body" because
it turns yellow after it releases the egg. It now becomes a temporary kind
of gland. It continues to make estrogen, but it really pumps out the hormone
progesterone ("the pregnancy hormone") The progesterone makes
the new uterine lining rich with nutrients needed to support an embryo.

Progesterone also signals the pituitary to stop sending LH, which is
what keeps the corpus luteum going. So the corpus luteum only lasts about
twelve days total, unless the egg is fertilized. As the corpus lutem begins
to die, it stops making progesterone and oestrogen. Without these hormones
the lining of the uterus begins to weaken, tiny blood vessels in it shut
down, and it begins to shed off. This shedding is menstruation. The uterus
sheds two thirds of its lining at each menstruation, leaving only the bottom
layer to grow again.

One the first day of menstruation, oestrogen levels are very low, and
the hypothalamus signals the pituitary gland to send off LH and FSH, and
it all begins again.

Disclaimer:All Information is provided for
educational purposes only and not intended
to be used for any therapeutic purpose, neither is it intended to diagnose,
prevent, treat or cure any disease. Please consult a health care
professional for diagnosis and treatment of medical conditions.
While attempts have been made to ensure the accuracy of this information,
The Health Information Network does not accept any responsibility for any errors or
omissions.